Keyboard, being the most common input interface available on the market, is vastly used in many electric devices, such as computers, person digital assistances, cellular phones, and so on. With the advance of technology, keyboard that can emit light are gradually becoming the mainstream product of keyboard manufacturing industry since it is well adapted to be used in an environment that is not so well illuminated. Such light-emitting keyboards are especially suitable to be applied in notebook computers as the notebook computer, being designed to be carried around and used in all kinds of environments possible, that are equipped with light-emitting keyboards can operate easily under any illumination conditions. In addition, for meeting the growing personalization requirements of today's consumers, light-emitting keyboards can be designed with a hint of amusement for enabling the same to operate with dashing visual effects.
Please refer to FIG. 1, which is a cross sectional view of a conventional light-emitting keyboard. As shown in FIG. 1, the conventional light-emitting keyboard 100 is comprised of: a light guide plate 110, a light emitting diode (LED) 120, a frame 130, and a reflector 140, in which the light guide plate 110 is configured with a light entrance surface 112, a light emitting surface 114, a bottom surface 116 and a side surface 118 whereas the light emitting surface 114 is arranged opposite to the bottom surface 116, and the light entrance surface 112 and the side surface 118 are arranged respectively next and connecting to the light emitting surfaced 114 and the bottom surface 116 while being sandwiched therebetween.
In addition, as the LED 120 is disposed next to the light entrance surface 112 of the light guide plate 110, a beam 122 emitted from the LED 120 will enter the light guide plate 110 through the light entrance surface 112 and then being reflected repetitively inside the light guide plate 110 until a beam 122a conforming with the breaking down of total reflection is formed and thus being discharge out of the light guide plate 110 through the light emitting surface 114 and then into the frame 130 for enabling the frame to radiate light. It is noted that the frame 130 is disposed on the light emitting surface 114 of the light guide plate 110.
During the reflection of the beam 122 inside the light guide plate 110, there will be a portion of the reflection, represented as the beam 122b in FIG. 1, being discharged out of the light guide plate 110 through the bottom surface 116 thereof. As shown in FIG. 1, the reflector 140 is arranged at a position for enabling the same to reflect the beam 122b back to the light guide plate so as to prevent the loss of energy. In this embodiment, the reflector 140 is disposed on the bottom surface 116 of the light guide plate 110. However, during the repetitive reflections, there is still a portion of beam, represented by the beam 122c, being discharged out of the light guide plate 110 through the side surface 118 thereof. Thus, there is still a portion of light emitted from the LED 120 being lost which can cause adverse affect to the overall brightness of the light emitting keyboard 100 as well as the lighting efficiency of the same.